A generic electrophotographic image forming apparatus removes toner adhering to a circumferential surface of a photosensitive drum (image bearing member) using a cleaning blade formed from rubber. As images are formed, at least one of paper dust from transfer sheets (for example, a mass of at least one of cellulose and a filler) and an external additive (for example, titanium oxide) of toner accumulate on and around an edge of the cleaning blade, that is, a portion of the cleaning blade that is in contact with the photosensitive drum. The amount of the accumulation varies from location to location in terms of a rotational axis direction of the photosensitive drum. Accordingly, a location with more accumulation may cause local scraping of the photosensitive drum by the accumulation. Repeated local scraping manifests as a scratch in a circumferential direction on the circumferential surface of the photosensitive drum. As a result, an output image formed on paper has a streak resulting from the scratch in the circumferential direction on the photosensitive drum. In order to form good output images over a long period of time, therefore, it is required to maintain the circumferential surface of the photosensitive drum smooth.
A cleaning blade in an image forming apparatus disclosed in Patent Literature 1 is caused to reciprocate in a rotational axis direction of a photosensitive drum. Accordingly, local accumulation on and around an edge of the cleaning blade can be moved in the rotational axis direction, preventing a local scratch in a circumferential direction from occurring on the circumferential surface of the photosensitive drum.